class CV
  def hv(a)
    4*a
  end
  def hcn(a,b)
    2*(a+b)
  end
  def ht(r)
    2*r*3.1415
  end
end
class DT
  def hv(a)
      a*a
    end
    def hcn(a,b)
      a*b
    end
    def ht(r)
      r*r*3.1415
    end
  
end